Under the Case Layout panel, scroll through until you find Visualforce Pages.

Now click and drag ConfAssociationCase onto a preferred section.

You can first drag a section and configure it. You may also want to adjust the properties so that you get a panel with a size you'll be more comfortable working in (a minimum height of 500px is recommended).

Once you're done, click Save.

You can now see the Confluence pages that are associated with the current Case, including pages that mention the current Case using the Using Salesforce Object macro.